I would really recommend going to the Smithsonian museums, especially the Air & Space Museum.

Depends on how much time you have. It would take weeks to just see everything at The Smithsonian on the mall, that would be a good place to start BTW.

The Philips Collection is also worth a side trip.

The Spy museum is also a lot of fun.

The Smithsonian National Zoo is great too,. You may just want to take some time to ride the Metro, visit Union Station, wander around and see some the places you’ve seen in movies, Like https://dc.curbed.com/maps/films-mo.....-washington-dc

I lived in Washington DC for a few years:

-As others say, the Smithsonian museums are very nice, notably the National Zoo and the Air and Space Museum

-Also visit the Hillwood Museum: an exceptional collection of Russian art, the largest collection of Imperial Russian artwork outside of Russia

-I would highly recommend, in DC proper, a visit to the National Cathedral, or in eastern DC, a visit to the Basilica of the National Shrine of the Immaculate Conception, a Minor Basilica declared such by John Paul II.

DC has an incredible selection of restaurants and is famous for its Ethiopian cuisine. Try something in DC that you couldn't find elsewhere. When it comes to Ethiopian restaurants, I highly recommend a locale known as Habeesha. It's very cheap and very delicious.

I'm not sure how late you're willing to be out, but the Lincoln Memorial (and the Mall in general) is especially beautiful after dusk, when all the lights are visible.

Arlington National Cemetery is worth a visit if you have time, lots of important people are buried there, you can visit Robert E. Lee's old plantation house and it has splendid views of the city.

All the Smithsonian museums would take forever (I've lived in the area for five years and still haven't even been in them all) but at least check out Air and Space and Natural History. The latter is the best imo but I'm biased cause I used to work there. I hear great things about African American History which opened recently, but I haven't been yet. There's also an amazing ramen place called Daikaya on 6th St NW if you're into that.

Agreed with Netolu above that the mall is great after dark, at least when it's warm outside. It's been a frozen wasteland all winter/spring, but you're going at just the right time because next week is all supposed to be 70's and 80's.

The war memorials. Don't forget the Korean one.

Air and Space is on top my list